Vascular hole closure device

ABSTRACT

A device for closing an aperture in a vessel wall, the aperture having an external opening in an external region of the vessel wall and an internal opening in an internal region of the vessel wall. The device includes a covering member positionable inside the vessel against the internal opening of the aperture and having a dimension to prevent egress of fluid through the aperture. A securing member is positionable external of the vessel and has a plurality of pores extending therethrough. A flexible connecting member operatively connects the covering member and securing member and moves the securing member toward the covering member.

This application claims priority from provisional application Ser. No. 61/330,477, filed May 3, 2010 and is a continuation in part of application Ser. No. 12/854,988, filed Aug. 12, 2010, which claims priority from provisional application Ser. No. 61/241,555, filed Sep. 11, 2009, and is a continuation in part of application Ser. No. 12/358,411, filed Jan. 23, 2009, which claims priority from provisional application Ser. No. 61/066,072, filed Feb. 15, 2008. The entire contents of each of these applications are incorporated herein by reference.

BACKGROUND Technical Field

This application relates to a vascular device and more particularly to a device for closing openings in vessel walls.

Background of Related Art

During certain types of vascular surgery, catheters are inserted through an incision in the skin and underlying tissue to access the femoral artery in the patient's leg. The catheter is then inserted through the access opening made in the wall of the femoral artery and guided through the artery to the desired site to perform surgical procedures such as angioplasty or plaque removal. After the surgical procedure is completed and the catheter is removed from the patient, the access hole must be closed. This is quite difficult not only because of the high blood flow from the artery, but also because there are many layers of tissue that must be penetrated to reach the femoral artery.

Several approaches to date have been used to close femoral access holes. In one approach, manual compression by hand over the puncture site is augmented by a sandbag or weight until the blood coagulates. With this approach, it can take up to six hours for the vessel hole to close and for the patient to be able to ambulate. This inefficiency increases the surgical procedure time as well as the overall cost of the procedure since the hospital staff must physically maintain pressure and the patient's discharge is delayed because of the inability to ambulate.

In another approach to close the vessel puncture site, a clamp is attached to the operating table and the patient's leg. The clamp applies pressure to the vessel opening. The patient, however, must still be monitored to ensure the blood is coagulating, requiring additional time of the hospital staff and increasing the cost of the procedure.

To avoid the foregoing disadvantages of manual pressure approaches, suturing devices have been developed. One such suturing device, referred to as “the Closer” and sold by Perclose, advances needles adjacent the vessel wall opening and pulls suture material outwardly through the wall adjacent the opening. The surgeon then ties a knot in the suture, closing the opening. One difficulty with the procedure involves the number of steps required by the surgeon to deploy the needles, capture the suture, withdraw the suture, and tie the knot and secure the suture. Moreover, the surgeon cannot easily visualize the suture because of the depth of the femoral artery (relative to the skin) and essentially ties the suture knot blindly or blindly slips a pre-tied knot into position. Additionally, the ability to tie the knot varies among surgeons; therefore success and accuracy of the hole closure can be dependent on the skill of the surgeon. Yet another disadvantage of this suturing instrument is that the vessel opening is widened for insertion of the instrument, thus creating a bigger opening to close in the case of failure to deliver the closure system. It is also difficult to pass the needle through calcified vessels.

U.S. Pat. No. 4,744,364 discloses another approach for sealing a vessel puncture in the form of a device having an expandable closure member with a filament for pulling it against the vessel wall. The closure member is held in place by a strip of tape placed on the skin to hold the filament in place. However, the closure device is still subject to movement which can cause leakage through the puncture. Additionally, if the suture becomes loose, the closure member is not retained and can flow downstream in the vessel. Moreover, since the suture extends through the skin, a potential pathway for infection is created. The closure device in U.S. Pat. No. 5,545,178 includes a resorbable collagen foam plug located within the puncture tract. However, since coagulation typically takes up to twenty minutes and blood can leak in between the plug and tissue tract, manual pressure must be applied to the puncture for a period of time, until the collagen plug expands within the tract.

It would therefore be advantageous to provide a device which would more quickly and effectively close openings (punctures) in vessel walls. Such device would advantageously avoid the aforementioned time and expense of applying manual pressure to the opening, simplify the steps required to close the opening, avoid widening of the opening, and more effectively retain the closure device in the vessel.

Commonly assigned co-pending patent application Ser. No. 10/847,141, filed May 17, 2004, discloses effective vascular hole closure devices which have the foregoing advantages. It would be further advantageous to provide a vascular hole closure device which is adjustable to accommodate different tissue thicknesses and applies a more constant clamping/retaining force between the intravascular and extravascular components of the device irrespective of tissue thickness.

SUMMARY

The present invention provides a device for closing an aperture in a vessel wall, the aperture having an external opening in an external region of the vessel wall and an internal opening in an internal region of the vessel wall. The device comprises a covering member having a longitudinal axis and positionable inside the vessel against the internal opening of the aperture, and having a dimension to prevent egress of fluid through the aperture. A securing member is positionable external of the vessel. The securing member has a plurality of pores extending therethrough. A flexible connecting member operatively connects the covering member and the securing member and moves the securing member toward the covering member.

In some embodiments, the covering member has a first opening, the first opening configured to restrict movement of the connecting member. A second flexible connecting member could be provided for moving the securing member toward the covering member.

In some embodiments, the covering member is composed of a resorbable material. In some embodiments, the securing member is composed of a mesh material. In some embodiments, the securing member is composed of a resorbable material. The connecting member can also be composed of a resorbable material.

In one embodiment, the securing member is substantially disc shaped in configuration. In another embodiment, the securing member is substantially rectangular in configuration.

The device can further include one or more retainers positioned proximally of the securing member. The device can also include first and second retainers. The retainer(s) can be spherical shaped, bullet shaped, pill shaped or other configurations. The connecting member can be connected to the retainer(s) to move the retainer(s) and securing member toward the covering member.

In another aspect, the present invention provides a device for closing an aperture in a vessel wall, the aperture having an external opening in an external region of the vessel wall and an internal opening in an internal region of the vessel wall. The device comprises a covering member having a longitudinal axis and positionable inside the vessel against the internal opening of the aperture and having a dimension to prevent egress of fluid through the aperture. First and second retainers are positionable external of the vessel. A flexible connecting member connects the first retainer to the covering member. A porous material is positioned between the retainers and the covering member. Preferably, pulling of the connecting member advances the first retainer toward the covering member.

In some embodiments, the covering member has an opening configured to restrict movement of the connecting member. In these embodiments, the connecting member can extend through first and second openings of the covering member and be connected to the securing member. The first opening can be configured to frictionally retain the connecting member to retain the position of the securing member with respect to the covering member.

The device may include a second flexible connecting member connecting the securing member to the covering member.

Preferably, the covering member is pivotable between a more longitudinal orientation for delivery and a transverse position for placement.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present disclosure are described herein with reference to the drawings wherein:

FIG. 1 is a perspective view of a first embodiment of the closure device of the present invention;

FIG. 2 is a cross-sectional view illustrating the suture extending through the covering member of FIG. 1;

FIG. 3 is a perspective view of the embodiment of FIG. 1 illustrating the sutures pulled proximally to move the securing member, toward the covering member adjacent the outer surface of the vessel wall;

FIG. 4 is a perspective view of an alternate embodiment of the closure device of the present invention;

FIG. 5 is a perspective view of another alternate embodiment of the closure device of the present invention;

FIG. 6 is a perspective view of yet another alternate embodiment of the closure device of the present invention; and

FIG. 7 is a perspective view of another alternate embodiment of the closure device of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in detail to the drawings where like reference numerals identify similar or like components throughout the several views, FIG. 1 is a perspective view of a first embodiment of the vascular hole (aperture) closure device of the present invention. The device is intended to close an aperture in the vessel wall, typically formed after removal of a catheter previously inserted through the vessel wall into the vessel lumen for performing angioplasty or other interventional procedures. The aperture extends through the patient's skin and underlying tissue, through the external wall of the vessel, through the wall of the vessel, and through the internal wall of the vessel to communicate with the internal lumen of the vessel. The closure device of the present invention has an intravascular component to block blood flow and an extravascular component to retain the intravascular component.

More specifically, the closure device includes a covering member or patch positioned within the vessel against the internal wall of the vessel to block blood flow and a securing member with openings or pores positioned external of the vessel wall to retain the covering member in its blocking position. The securing member is fixedly attached to a flexible connecting member such as a suture such that pulling of the suture advances the attached securing member toward the covering member to ultimately position the securing member either against or adjacent the external surface of the vessel wall. The plurality of pores in the securing member facilitates movement toward the covering member as tissue can enter between the pores. Thus, the fat molecules can enter allowing the securing member to track down easier through the tissue tract.

Turning to FIGS. 1-3, a first embodiment of the closure device of the present invention is illustrated. Hole (aperture) closure device 10 has a covering member or patch 40 and a securing member 20. The securing member 20 in this embodiment is in the form of a disc having substantially planar upper and lower surfaces 24, 26, respectively, although radiused surfaces or irregular surfaces are also contemplated. Covering member or patch 40 is dimensioned and configured for positioning inside the vessel on the internal side of the vessel aperture against the internal wall of the vessel; the securing member 20 is configured to be positioned outside the vessel wall adjacent or contiguous the external side of the vessel aperture.

Covering member 40, preferably elongated in configuration as shown, is retained in a delivery sheath in a longitudinal position for delivery to the vessel, and then pivots to a transverse position within the vessel lumen (substantially perpendicular to an axis extending through the aperture) for orientation to cover (patch) the vessel aperture on the internal side. This movement is illustrated in FIGS. 37A-37D of commonly assigned co-pending patent application Ser. No. 10/847,141, filed May 17, 2004, issued as U.S. Pat. No. 7,662,661, the entire contents of which are incorporated herein by reference (hereinafter the '141 application).

The elongated covering member 40 functions to cover (patch) the internal opening in the vessel wall to prevent the egress of blood. With reference to FIG. 1, the covering member 40 is preferably somewhat oval shaped with elongated substantially parallel side walls 42 a, 42 b and end walls 49 a, 49 b, illustratively curved, connecting the side walls 42 a, 42 b. Other shapes of the covering member are also contemplated. Covering member preferably has a thicker region 43 in the central region than the first and second end regions 45, 47. Other dimensions are also contemplated.

The longitudinal axis of covering member 40 defines a lengthwise dimension and transverse axes define a shorter widthwise dimensions. The widthwise dimension of the covering member 40 can be for example about 2.5 mm (for a 6 Fr device). In a preferred embodiment, the covering member 40 is about 3.1 mm in widthwise dimension. Other dimensions are also contemplated. The width preferably is at least substantially equal to the dimension of the internal opening in the vessel wall to effectively cover the opening. In a preferred embodiment, the covering member 40 has a length of about 8.6 mm (in a 6 French system). Other dimensions are also contemplated.

It should be appreciated that alternatively the covering member could be provided with an enlarged width region as illustrated in the embodiment of FIG. 1 of the '141 application. The covering member could also be configured asymmetrically so that the enlarged region is off-centered to accommodate widening of the aperture as the member is pulled at an angle. The covering member could also be configured in a paddle shape with a narrowed region adjacent a wider region as in FIGS. 9B-9E of the '141 application. Other covering member configurations including those disclosed in the '141 application could be utilized with the securing members of the present application.

The elongated covering member can be composed of materials such as polycarbonate or polyurethane. Preferably it is composed of resorbable materials such as lactide/glycolide copolymers that after a period of time resorb in the body. If composed of resorbable material, the covering member could optionally have regions of varying resorbability. Varying degrees of resorbability can be achieved for example by utilizing different materials having differing resorbable characteristics or by varying the mass of the covering member (increased mass increases resorbtion time).

Securing member 20 is preferably composed of resorbable material. The securing member can be composed of a material having a plurality of pores extending therethrough. This can include a mesh, braid, or weave for example. It can also include a more solid material having pores formed therethrough. Materials include Polydioxanone (PDO), Polylactic acid (PLA), Polyglycolic Acid (PGA), Poly(lactic-co-glycolic acid) (PLGA), Polyhydroxyalkanoates (PHA), and Polycaprolactone (PCL), although other materials are contemplated. It could also be made of non-absorbable polymeric or metallic material.

When the securing member 20 is released from the delivery instrument, it is spaced further from the covering member 40. It is configured to then be advanced toward the covering member 40. More specifically, securing member 20 is fixedly secured to flexible connecting members illustratively in the form of suture 30 and 32. Sutures 30, 32 are preferably made of polymeric material and are preferably resorbable, composed of a material such as polydioxanome. It is also contemplated that alternatively a metallic material could be utilized. It is also contemplated that a single suture could be utilized to advance the covering member.

As shown, suture 30 has a free end 30 a and an opposite end 30 b secured to securing member 20 by molding, gluing, forming a knot, or other methods. Similarly, suture 32 has a free end 32 a and an opposite end 32 b secured to securing member 22 in a similar manner. The sutures 30, 32 are looped through the covering member 40. Other methods of attachment are also contemplated. For example, the sutures can be attached to covering member by a loop of suture as shown for example in FIG. 8 of co pending patent application Ser. No. 12/854,988, filed Aug. 12, 2010 (hereinafter the “'988 application”), incorporated herein by reference in its entirety.

To advance the securing member 20 toward the vessel wall W (and covering member 40), the free end 30 a, 32 a of each suture is pulled proximally (in a direction of the arrows of FIG. 3, thereby moving the securing member 20 in the opposite direction closer to the aperture and vessel wall. The pores of securing member 20 facilitate advancement toward the covering member 40 as tissue can enter between the pores as it is advanced. Once tightened against the tissue, a sufficient retention force is maintained, i.e. a proximal pulling force on the covering member 40 to pull it slightly upwardly (proximally) against the vessel wall. The securing member 20 therefore helps to prevent the covering member 40 from separating from the vessel wall (e.g. moving in the direction toward the opposing vessel wall) which could create an unwanted gap between the covering member 40 and the vessel opening to allow blood flow. The extent to which the securing member 20 moves toward the wall (and thus the distance from the vessel wall in its final placement position) will depend on the tissue thickness. Thus, the closure device 10 can adjust for different tissue thicknesses and apply a constant retention force regardless of tissue thickness.

The delivery instrument for inserting the closure device extends through an opening in the skin, through the tissue tract to the vessel, through an external opening in the vessel wall, through the aperture in the vessel wall, and through an internal opening on the internal side of the vessel wall into the vessel lumen.

The covering member 40 is outside a retainer tube and within a delivery sheath in a tilted position in a manner similar to FIGS. 2 and 3 of the '988 application. The covering member 40 emerges from the sheath and moves from a tilted and preferably a somewhat straightened positioned, (substantially aligned with the longitudinal axis of the sheath) to a transverse position within the vessel (see the orientation of FIG. 3). (Note the vessel wall is shown in FIG. 3 but the rest of the vessel and tissue are removed for clarity.) The securing member 20 remains within the tube in a tilted somewhat straightened position. In some embodiments, the securing member 20 can be retained within the tube in a folded or compressed configuration. Note the covering member 40 can be ejected by a pusher (not shown) contacting the side or top wall of the covering member 40.

As shown in FIG. 3, covering member 40 is pulled proximally to abut the internal opening on the internal side of the vessel W to cover (patch) the opening and the sutures 30, 32, extend through the opening A in the vessel wall. The securing member 20 is ejected from the sheath by advancing the securing member 20, retracting the sheath or relative movement of both to free the securing member 20 from the confines of the sheath. As noted above, in the delivery position, the securing member 20 is preferably in a tilted position (not shown) to minimize the transverse dimension of the delivery system and tilts to a transverse deployment position when exposed from the delivery sheath. As also noted above, the securing member 20 can alternatively or additionally be held in a folded or compressed position.

Then, to retain the covering member 40 in position against the vessel wall to block blood flow therethrough, sutures 30 and 32 are pulled proximally from their free ends 30 a, 32 a, in the direction of arrows of FIG. 3 thereby advancing the securing member 20 distally in the direction toward the aperture A, vessel wall W and covering member 40. As shown, the securing member 20 can be moved to a position contiguous to the vessel wall, or depending on tissue thickness, may be adjacent the wall with some tissue interposed between the securing member 20 and vessel wall. The securing member 20 in this position applies a proximal (upward) force on the elongated covering member 40 to limit movement of the covering member into the vessel.

The covering member 40 has a first pair of holes 44 a, 44 b and a second pair of holes 46 a, 46 b. The first pair of holes 44 a, 44 b receive suture 32 and the second pair of holes 46 a, 46 b receive suture 30. Holes 44 b, 46 b have a smaller diameter than holes 44 a, 46 a, respectively. The larger hole 46 a is dimensioned to receive suture 30 for free unrestricted movement of the suture 30 therethrough and therefore easier application of securing member 20. Similarly, the larger hole 44 a is dimensioned to receive suture 32 for free unrestricted movement of the suture 32 therethrough. Smaller hole 46 b is dimensioned to frictionally engage suture 30 so that tension is applied to the suture 30. It is dimensioned so that the suture 30 can be pulled through the hole 46 b if sufficient force is applied by pulling on free end 30 a, but if such predetermined force is not applied, the suture 30 will remain frictionally engaged within the wall of the hole 46 b and not move, and thus securing member 20 will not move. Hole 44 b operates similarly with respect to suture 32, allowing movement if a predetermined force is applied but remain frictionally engaged if such force is not applied. In this manner, when the user ceases pulling on free ends 30 a and 32 a of sutures 30, 32 respectively, the securing member 20 will remain in position. FIG. 2 shows how the suture 30 is looped through the respective opening.

To enhance the retention of the suture of the present invention within the smaller diameter hole, a plurality of internal teeth can be provided. This is shown for example in FIGS. 22 and 23 of the '988 application wherein hole 496a′ has a plurality of teeth 497 formed on the interior wall of the smaller opening. Engagement of the suture 430′ by the teeth 497 retains the suture and retainer. Note that the teeth can be formed to angle inwardly so the suture can be moved in only one direction, i.e. proximally so the retainer is advanced toward the covering member.

The alternate embodiment of FIG. 4 of the present invention is identical to the embodiment of FIG. 1 except for the configuration of the securing member. Thus, closure device 100 has a covering member or patch 140 identical to patch 40, sutures (flexible connecting members) 130, 132 (with free ends 130 a, 132 a) identical to sutures 30, 32 and openings 146 a, 146 b and 144 a, 144 b identical to openings 46 a, 46 b, 44 a, and 44 b. Therefore, further detail of these components and their function, for brevity, will not be repeated herein. The securing member 120 differs from securing member 20 of FIG. 1 in that it is substantially rectangular in shape. Securing member 120 can optionally have substantially planar upper and lower surfaces 124, 126, although other surfaces can be provided, e.g. curved, concave, convex, etc. The pores in securing member 120 facilitate movement in the same manner as described above. The securing member 120 can be made of the same materials as discussed above with respect to securing member 20. Sutures 130, 132 advance securing member 120 toward covering member 140 in the same manner as sutures 30, 32 discussed above.

The alternate embodiment of FIG. 6 is identical to the embodiment of FIG. 1 except for the configuration of the securing member. Thus, closure device 200 has a covering member or patch 240 identical to patch 40, sutures (flexible connecting members) 230, 232 (with free ends 230 a, 232 a) identical to sutures 30, 32 and openings 246 a, 246 b and 244 a, 244 b identical to openings 46 a, 46 b. 44 a, and 44 b. Therefore, further detail of these components and their function, for brevity, will not be repeated herein. The securing member 220 is shaped similarly to patch 240 (except inverted) with a thicker central region 225 and substantially parallel side walls 227, 229 connected by radiused walls 226 a, 226 b. An opening 223 in central region 225 facilities advancement as tissue can enter the opening 223 as securing member 220 is advanced. Additional openings or pores could also be provided to facilitate movement. The securing member 220 can be made of the same materials as discussed above with respect to securing member 20. Sutures 30, 32 advance securing member 220 toward covering member 240 in the same manner as sutures 230, 232 discussed above.

In the embodiment of FIG. 5, hole closure device 300 has a covering member or patch 340 substantially identical to patch 40 and a securing member 320 with pores similar to securing member 120 of FIG. 3 to facilitate advancement. Openings 346 a, 344 a are larger than openings 346 b, 344 b. The openings are dimensioned to receive sutures (flexible connecting members) 330, 332. That is, suture 330 extends through openings 346 a and 344 b and suture 332 extends through openings 344 a, 344 b. Sutures 330, 332, have free ends 330 a, 332 a, respectively. Openings 344 b and 346 b have a smaller dimension to frictionally engage the suture as described above with respect to openings 44 b, 46 b of FIG. 1. First and second retainers 360, 370 are spherical shaped and positioned proximally of securing member 320, but it is also contemplated other shaped retainers could be utilized, e.g. cylindrical, pill shaped, etc. Optionally one retainer could be provided. Thus, securing member 320 is interposed between the retainers 360, 370 and patch 340. The sutures 330, 332 are attached at one end to retainers 360, 370, respectively and can extend through pores in the securing member 320 to loop through covering member 340. The securing member 320 remains external of the vessel opening and further functions as an extravascular component to block the retainers 360, 370 from extending through the vessel opening into the vessel. Proximal force applied to sutures 330, 332 at their free ends 330 a, 332 a advances retainers 360, 370 toward covering member 340 in the same manner as sutures 30, 32 of FIG. 1 advance securing member 20, due to their attachment to retainers 360, 370 at their opposite end. As retainers 360, 370 are advanced toward covering member 340 they force securing member 320 toward covering member 340 due to their engagement (abutment) with the proximal surface 321 of securing member 320.

In the embodiment of FIG. 7, a single retainer 420 is provided in the form of a substantially cylindrical shaped member having pores to facilitate movement as described above. Member 420 is attached to a first portion of suture (flexible connecting member) 430 by a suture loop 432 extending through the pores or through openings in retainer 420 and looped as shown. Suture 430 extends through a channel in member 420 and extends through large opening 444 a in covering member or patch 440, exiting smaller opening 444 b, terminating in free end 430 a. Thus, free end 430 a of suture 430 is pulled proximally, pulling retainer 420 toward covering member 440, with the smaller opening 444 b frictionally retaining the suture 430 in the same manner as opening 44 b in FIG. 1 to restrict movement.

While the above description contains many specifics, those specifics should not be construed as limitations on the scope of the disclosure, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision many other possible variations that are within the scope and spirit of the disclosure as defined by the claims appended hereto. 

1-18. (canceled)
 19. A device for closing an aperture in a vessel wall, the aperture having an external opening in an external region of the vessel wall and an internal opening in an internal region of the vessel wall, the device comprising: a covering member having a longitudinal axis and positionable inside the vessel against the internal opening of the aperture, the covering member having a dimension to prevent egress of fluid through the aperture; a securing member positionable external of the vessel, the securing member having a plurality of pores; and a flexible connecting member operatively connecting the covering member and the securing member, the flexible connecting member being fixedly secured to the securing member at one end, wherein the flexible connecting member moves the securing member toward the covering member as a second end of the flexible connecting member is moved proximally as the securing member remains fixedly secured to the flexible connecting member at the first end, in a placement position the securing member securing the covering member in position and remaining proximal of the covering member.
 20. The device of claim 19, wherein the covering member has a first opening, the first opening configured to restrict movement of the connecting member.
 21. The device of claim 19, wherein the covering member is composed of a resorbable material.
 22. The device of claim 21, wherein the flexible connecting member is a suture and is composed of a resorbable material.
 23. The device of claim 19, wherein the covering member has a substantially planar surface.
 24. The device of claim 19, wherein the securing member is composed of a resorbable material.
 25. The device of claim 19, wherein the securing member is composed of a mesh.
 26. The device of claim 19, wherein the covering member is pivotable between a more longitudinal orientation for delivery and a transverse position for placement.
 27. The device of claim 19, wherein the covering member has a length greater than a width.
 28. The device of claim 19, wherein a central region of the covering member is thicker than a peripheral region.
 29. The device of claim 19, wherein the covering member has first and second openings, the flexible connecting member extending through the first and second openings, the first opening configured to frictionally retain the flexible connecting member to retain the position of the securing member with respect to the covering member.
 30. The device of claim 19, further comprising a second flexible connecting member operatively connecting the covering member and the securing member, the second flexible connecting member being fixedly secured to the securing member at one end, wherein the second flexible connecting member moves the securing member toward the covering member as a second end of the second flexible connecting member is moved proximally as the securing member remains fixedly secured to the second flexible connecting member at the first end.
 31. The device of claim 30, wherein the second flexible connecting member is looped through the covering member.
 32. The device of claim 19, wherein the covering member has first and second openings to receive the flexible connecting member, the first opening having a size different than a size of the second opening.
 33. The device of claim 32, wherein the covering member has third and fourth openings to receive the second connecting member, the third opening having different size than the second opening.
 34. The device of claim 33, wherein the first and third openings frictionally a respective flexible connecting member and the third and fourth openings are dimensioned for free unrestricted movement of the flexible connecting member.
 35. The device of claim 34, wherein the third opening has a larger cross-sectional dimension than the first opening and the fourth opening has a larger cross-sectional dimension than the second opening. 